During a PIA flight (PK-787) from Dubai to London, the co-pilot temporarily left the cockpit to use the restroom, during which time the aircraft's navigation system inadvertently switched from 'INS mode' to 'Heading Mode.' This went unnoticed until five minutes after the co-pilot returned, at which point the crew discovered they had drifted 130 miles north of their planned track, resulting in an unauthorized flight over the restricted airspace of the Nagorno-Karabakh region in Azerbaijan. The crew quickly corrected their course with the help of VORs and Ankara air traffic control, returning to their approved route and landing at Heathrow only three minutes behind schedule; the airspace violation was later officially reported to CAA Pakistan by the Azerbaijan CAA.
